TW200846068A - Exhaust gas purification catalyst, and catalytic honey-comb structure for exhaust gas purification - Google Patents

Abstract

Disclosed are: an exhaust gas purification catalyst which is an inexpensive three-way catalyst, which contains a reduced amount of an expensive noble metal, particularly does not use Pt, and contains no expensive rare earth element, and which has the same level of catalytic activity as that of a conventional one; and a catalytic honey-comb structure for exhaust gas purification.; Specifically disclosed are: an exhaust gas purification catalyst comprising (A) an oxide M(Co1-yFey)O3-d [wherein M represents a combination of an element substantially selected from Ba and Sr; y represents a number of 0 to 1; and drepresents a value that is so defined as to satisfy the charge neutrality condition] carrying one or two noble metals selected from Pd and Rh and (B) active alumina carrying one or two noble metal selected from Pd and Rh; and a catalytic honey-comb structure for exhaust gas purification, which is produced by wash-coating the exhaust gas purification catalyst onto a ceramic- or metal-made honey-comb.

Description

200846068 IX. INSTRUCTIONS: TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for purifying carbon monoxide 5 (CO), nitrogen oxides (NOx) and unburned hydrocarbons (HC) in combustion exhaust gas. Medium and honeycomb catalyst structure - especially for a catalyst for the purification of carbon monoxide (CO), nitrogen oxides (NOx) and unburned hydrocarbons (HC) and honeycomb catalysts from internal combustion engines such as automobile engines. Construct.

[lltr H 10 BACKGROUND OF THE INVENTION Gases emitted from internal combustion engines such as automobile engines contain CO, N0X, and HC. The commonly known catalyst technology converts c〇, NOx, and HC into carbon dioxide (C〇 2) Nitrogen (N2) and water (H2〇) reduce the emission of CO, NOX & HC. This catalyst technology can be used not only in the exhaust gas from the internal combustion engine, but also in other combustion exhaust gases. Simultaneously purifying the three-way catalyst system of CO, NOx, and HC in automobile exhaust gas> Widely using a catalyst in which precious metals such as Pt, Pd, and Rh are combined, and these noble metals are carried in the form of fine particles. Activated alumina (r-cerium oxide aluminum, lanthanum-alumina, %-alumina, π-alumina, (5-alumina, y 20 /C oxidized, 0 - oxidized, amorphous oxidized, etc.) The surface of the oxide particles is used by a wash coating on a metal or ceramic honeycomb. The ternary catalyst acts effectively close to the theoretical air-fuel ratio, and the air fuel is expanded in order to expand its effectiveness. The specific amplitude (ventilation) also includes an oxygen storage material such as 200846068 • t钸 oxide to enhance the catalytic performance. For example, Japanese Laid-Open Patent Publication No. SHO 54-159391 discloses a Yubei Metal/> Read Oxidation (4) Oxide Catalyst Tow adds an appropriate amount of oxidized material, although the fine oxide wire can impart oxygen absorbing ability and enhance the catalytic property. 5 However, it does not reduce the amount of precious metal. Currently in addition to cerium oxide The oxides of the outer layer are also reviewed for composite oxides, in particular, the review of composite oxides containing a rare earth element in the perovskite structure. For example, in order to enhance the activity of the ternary catalyst, U.S. Patent No. 2005-205280 There is disclosed a catalyst for supporting a perovskite-type composite oxide containing (7) LaAli-xMx〇3 (M: Group 1 to Group 5, Group 12 to Group 14), respectively. A high catalyst activity is obtained, and a calcium-containing rare earth element such as (La'Sr)Fe〇3 or (La,Sr)Mn〇3 is disclosed in Japanese Patent Publication No. 2006-36558. In addition to the composition of the above-mentioned (La,Sr)Fe03 or (La,Sr)Mn03 15 or the addition of elements and improvement of its long-term or heat resistance (JP-2003-Lu 175337) In order to enhance the long-term activity of the catalytic activity of precious metals, it is revealed that a composite oxide of noble metal RhiLa(Fe, Hh)0d is taken into the perovskite crystal lattice (JP-2004-41866) , JP-A-2004-41867). As mentioned above, although the perovskite type is complex The oxide can be selected from a plurality of elements. However, in order to effectively enhance the catalytic performance of the ternary catalyst, it is necessary to have a rare earth element such as La. It is disclosed in Japanese Laid-Open Patent Publication No. 2005-66559 that the AMxOy is not contained in the rare earth element. (A · · metal or soil test metal, M : Fe, Co or Ni) composite oxide, especially spinel AMxOy composite oxide combined with precious metal, 6 200846068 can effectively remove exhaust gas from diesel engines The particulate matter of the particulate matter and the nitrogen oxides, however, have not been suggested to be capable of purifying the catalytic properties of the three-way catalyst of CO, HC and NOx at the same time as the exhaust gas purification of a gasoline engine or the like. In order to effectively purify CO, HC and NOx in the exhaust gas, it is known that the Ternary touch 5 medium uses a noble metal mainly composed of Pt (Rh and Pd other than Pt), and accordingly, if a large amount of precious metal is used, Catalyst performance will increase, but the cost will also increase at the same time. That is, the proportion of exhaust gas purifying converters will increase in the price structure of engine systems such as automobiles. Therefore, as mentioned above, the combined calcium is currently reviewed. Titanium-type composite oxides and noble metals enhance the performance of ternary catalysts. However, among the perovskite-type composite oxides reviewed so far, high-priced rare earth elements are necessary, and the problem is that the rows are not lowered. The cost of gas purification conversion benefits. Further, although the catalytic performance can be improved by the cerium-type composite oxide containing a rare earth element, the current state of the art does not necessarily reduce the amount of precious metal used to reduce the cost of the exhaust gas purifying converter. 15 Further, as described in JP-A-2005-66559, a composite oxide containing no rare earth elements has been developed as an exhaust gas purification catalyst. However, it removes particulate carbon (4) from the diesel exhaust gas. When nitrogen oxides are used to simultaneously purify C 〇, HC, and NOx in the exhaust gas, even when combined with a noble metal, sufficient catalyst activity cannot be obtained. In the above composite oxygen 20 compound, it is generally estimated that the oxidation of the particulate carbon material, the adsorption accumulation of NOx, and the reductive decomposition of the adsorbed NOx all occur on the surface of an oxide. However, it is known from the inventor's review. It is extremely difficult to simultaneously carry out the oxidation reaction on the surface of one catalyst, and to reduce the reaction. If the catalytic activity of either one is increased, the activity of the other catalyst cannot be fully raised 7 200846068 liters. Further, it can be seen that when the AMxOy is also directly used as a ternary catalyst, it is impossible to simultaneously purify all of CO, HC, and NOx. H 明内 3 SUMMARY OF THE INVENTION 5 The present invention has been made in view of the foregoing problems, and an object thereof is to provide a

The use amount of the high-priced precious metal, in particular, a low-cost three-way catalyst which does not use Pt and does not contain a high-priced rare earth element, and has a catalyst for exhaust gas purification and a honeycomb for exhaust gas purification having the same level of catalyst activity as conventionally known. Catalyst structure. The inventors have found that by combining a composite oxide containing a Pt-free metal and an active oxidation carrying a noble metal not containing Pt, it is possible to exhibit higher catalytic activity than monomeric catalyst activity, respectively. The present invention has been completed. The present invention constitutes the following gist. (1) The catalyst for purifying a gas of the Qing Dynasty contains the oxide of the noble metal of the group holding the bite or the two kinds of oxides M (c〇i And < δ (here, the combination of elements selected from Ba or Sr, and (a), (iv) the value of the charge-neutral condition) (A); and the precious metal holding the ruthenium (A) The catalyst for exhaust gas purification according to the above item (1), wherein the noble metal of the compound W is fine, and the noble metal of the ruthenium oxide is Rh. The A/B mass ratio of 10 is 0.1 (4) The catalyst for exhaust gas purification according to the above item (1), wherein the y value is 8 200846068 0.2 to 1 〇 (5) - a honeycomb catalyst structure for exhaust gas purification, The above-mentioned (1) to (4) of the exhaust gas net touch (four) is applied to the shout or metal honeycomb to form. 5 (6) as in the aforementioned item (5) exhaust With a catalyst of honeycomb structure, wherein the honeycomb purifying the exhaust gas of the D-side human ratio Α / Β mass ratio of the catalyst used

The ratio of R1 to the α/β mass ratio of the exhaust gas purifying catalyst on the gas outlet side (10) R1/R2 is more than 1 and is 1 Torr or less. (7) The honeycomb catalyst structure for exhaust gas purification according to the above item (5), wherein the Α/Β贝里 ratio is the gas amount of the catalyst for exhaust gas purification, and the gas is from the gas of the Lishen honeycomb. The inlet side is inclined toward the gas outlet side, and the coating amount of the exhaust gas purifying catalyst is inclined and decreased from the gas outlet side of the honeycomb to the gas inlet side, and R1/ The ratio of R2 is greater than 1 and less than 100. 15 (8) - The type of exhaust purification department nest display structure, will be __ or

Rh of precious metals of the species or two kinds of oxides y yFey) () 3 - δ (where w is substantially selected from the combination of elements of B_r, and _~, the system is set to satisfy the charge condition (A) is thinly applied to the gas enthalpy side of the m metal honeycomb and is thinly coated on the gas outlet side of the honeycomb of the honeycomb or one of the two or two kinds of active oxidation _) . (9) The honeycomb catalyst structure for exhaust gas purification according to the above (8), wherein the noble metal supported on the oxide (A) is Pd, and the noble metal supported on the active oxidation (B) is Rh. (10) The honeycomb catalyst structure for exhaust gas purification according to Item (8), wherein the y value is 0.2 to 1. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the operation of the exhaust gas purifying catalyst 5 of the present invention on the honeycomb substrate and illustrating the exhaust gas purifying reaction. • Fig. 2(a) shows that the two types of A/B mass ratios of the milk discharge of the present invention are differently applied to the gas inlet side and the outlet side of one honeycomb _ exhaust purification honeycomb A schematic perspective view of the structure. Fig. 2(b) is a schematic view showing the honeycomb structure for exhaust gas purification in which the exhaust gas of the exhaust gas of the present invention having a different A/B mass ratio is differently applied to the gas inlet side and the outlet side of one honeycomb Partial cross-section of the interior of the hive. Fig. 3(a) is a schematic perspective view showing a honeycomb structure for exhaust gas purification in which the amount of the exhaust gas purifying catalyst of the present invention, which is different in the A/B mass ratio, is applied, and the coating amount is inclined. 15(b) is a schematic diagram showing the internal part of the honeycomb structure of the honeycomb structure for exhaust gas purification in which the two types of A/B mass ratios are differently coated with the exhaust gas purifying catalysts of the present invention. Sectional view. The third embodiment (C) shows a honeycomb structure for purifying exhaust gas purifying which is coated with the exhaust gas purifying catalyst of the present invention in which the two kinds of A/B mass ratios are different, and the coating amount is inclined. A partial cross-sectional view of the interior of the honeycomb is indicated. Figure 4(a) shows the thin coating of the noble metal-containing Aey) 〇3-5 composite oxide (A) on the gas inlet side of the honeycomb, and the activated alumina carrying the noble metal (B). A schematic perspective view of a honeycomb structure for exhaust gas purification which is thinly applied to the gas outlet side of the honeycomb. 200846068. The fourth system shows that the M(c〇i_yFey)〇3-5 composite oxide (A) carrying the noble metal of the present invention is thinly coated on the gas inlet side of the honeycomb, and oxidizes the active metal carrying the noble metal. A partial cross-sectional view of the inside of the honeycomb of the honeycomb structure for exhaust gas purification in which the aluminum is thinly applied to the gas outlet side of the honeycomb. [Embodiment] Detailed Description of the Preferred Embodiment As shown in the schematic view of Fig. 1, the exhaust gas purifying catalyst of the present invention contains φ: one or two kinds of noble metals carrying Pd*Rh ( C〇1-yFey)〇3 ^ of composite oxide (A); and activated alumina (B) carrying one or two kinds of noble metals of Pd4Rh. That is, in the figure, a catalyst containing a catalyst (A) and a catalyst (B) is formed on the honeycomb substrate 5, and the catalyst (A) is supported by a noble metal 1 (M). The 〇1-yFey) 〇3_5 composite oxide 2 is formed, and the catalyst (B) is formed by the activated alumina 4 carrying the noble metal 3. If only the composite oxide (A) carrying the noble metal is carried, the oxidation reaction of 15 CO and HC can be sufficiently performed, but only a slight reduction reaction is carried out, and the other aspect is only The activated alumina (B) carrying a noble metal not using Pt can perform all the reactions of the oxidation reaction of CO, the oxidation reaction of HC, and the reduction reaction of ruthenium. However, if the space velocity (SV) is increased, It cannot be fully purified and the catalyst activity is insufficient. However, if the catalyst of the present invention containing both (Α) and 2〇(B) is used, it can constitute more than the unconditionally complementary two catalysts.

Catalyst performance of the performance of the 忐, and the performance of the ternary catalyst performance level D. It is generally concluded that the high catalyst performance of this addition is achieved by holding the precious metal in the above-mentioned carrier. The surface of the composite oxide (Α) mainly promotes the oxidation reaction of CO into C〇2 and the partial oxidation reaction of HC. The surface of the activated alumina (B) carrying the noble metal is mainly the foregoing. Partially oxidized HC (HCOx) reduces NOx, that is, although it acts as a ternary catalyst only by carrying the active emulsification (B) of the genus Guimu, however, '5 if there is IV^Coi - yFedO3-5 composite oxide (a), generally inferred by (1) a large amount of partial oxidation Hc effective for the reduction of n〇a; (1) 复合 in M(Co丨-yFey)〇3 -, composite oxidation The oxidation reaction between c〇 and hc occurs on the surface of the substance (A), so the surface of the activated alumina (B) reduces the burden of the same oxidation reaction and can be utilized in a large amount in the N〇x reduction reaction, and can effectively clean the CO 10 CO , HC and ΝΟχ in the present invention M (C〇1_yFey) 〇 3 - $, ^ ^ is selected from the combination, and y is 0 1,5 is set to satisfy the value of the charge neutral condition in accordance with the y value, and, in view of the catalytic activity, the beigu 7 is particularly preferably in the range of 〇·2 ～1, and is more desirable. It is Oj,! Further, the structure of the composite oxide of m(c〇i 15 -yFey)〇3-5 is not particularly limited, however, it is preferable that at least a part thereof has a perovskite structure. In order to efficiently carry the particle size of the noble metal 'M(C〇1 - yFey) 03_5 composite oxide, the size of the average particle diameter 〇·5~ is preferably M(c.Bu A). The specific surface area of the composite oxide material is preferably in the range of 1 to 2 〇 m 2 /g. The noble metal of the composite oxide of M(Co]-yFey) 〇3-5, or the noble metal of the compound or the metal, or the preferred one is pd. The particle size of the genus of the genus is preferably in the range of 1 to 3 nm in average. The amount of the noble metal supported is not particularly limited. However, it is preferably 100 parts by mass relative to the composite oxide. ~2 〇 parts by mass. 12 200846068 There is no special restriction on the active oxidation of the present invention. The average particle size is 0 5~m, and the temperature is 20 U5 3.0_, and the range of active oxidation is l_i2/g. (product is 60~

Seven kinds of noble metals supported by active oxidation or a noble metal of Rh. 2-species read as ideal Rh. The particle size of the noble metal of the target is in the range of 1 to 3 nm, and the amount of the noble metal is not more than the above, but it is preferably 0.1 to 1.5 parts by mass relative to the above-mentioned neo-oxygen. η 10 15

20 In particular, the combination of the M(C〇1-yFey)〇H complex oxygen species (A) carrying Pd and the finely loaded active oxide paste can improve the selectivity of each of the above catalyst activities. Therefore, the catalyst activity can be further improved. In the present invention, the m (Cgi_^) 〇 "composite oxide L and the active oxidative charge carrying the noble metal of the noble metal are preferably A/B mass ratio 〇1 ～1 ,, if less than (U, then Since the presence of M(~ =ey)〇3_0 hard oxide (4) carrying precious metals is reduced, it is sometimes impossible to pass to the South Catalyst, which is black, and if it is greater than 1〇 , because the activity of carrying the noble to the genus will be reduced, it will sometimes reduce (10) X purification. The present invention has flatness performance even when it does not contain an oxygen absorbing material such as cerium oxide, and suggests that it is different from a conventional catalyst material, and of course, it may be used by containing an oxygen absorbing material. The M(Co!—yFey)〇H composite oxide of the present invention may be any of a liquid phase method such as a solid phase reaction method, a coprecipitation method or a sol-gel method, a chemical vapor deposition method, a laser stripping method, or the like. A method for manufacturing, for example, the following is a method for manufacturing a solid phase reaction method and a common sedimentation method. 13 200846068 In the production by the solid phase reaction method, the starting material can be an oxide of cerium or a hydroxide. Materials, carbonates, nitrates, organic acid salts, sulfates, etc., oxides of Co and Fe, hydroxides, nitrates, sulfates, etc., and weigh and mix the raw material powders of the foregoing bismuth and the foregoing ( ^ and the initial raw material of & to form the desired composition, and then perform the preliminary firing in the range of 600 to 1200 ° C. The mixing of the initial raw materials may be either wet or dry, if For the existing method, such as a spider mix, a ball mill, or a planetary ball mill, the M(c〇i yFey)〇3•^ composite oxide obtained by preliminary calcination may be pulverized and classified according to the situation. And use it. 10 The manufacture, the starting material may be used nitric acid Μ

Salt, acid salt, organic acid salt, etc., nitrate and sulfate of Co and Fe, sulfate, hydroxide, chloride, chelate complex, organic acid salt, etc. The starting materials of c〇 and pe are formed into a desired composition and dissolved in water, and a pH adjusting agent is added to make the pH 15 of the solution neutral to alkaline, and the dissolved ions of Co, Fe and Fe are co-formed. precipitation. The coprecipitate is separated by filtration or centrifugation, washed and dried, and then subjected to preliminary calcination in the range of 600 to 1200 C, and the MCoi-yFejO 3 -5 composite oxide obtained by preliminary calcination is required. It is pulverized, classified, and used. 20 The method of supporting the noble metal on the M(Coi - yFey) 03 - θ composite oxide is not particularly limited, and for example, it can be carried by the following method. A water-soluble precious metal salt such as a nitrate, a vapor, an acetate, a sulfate or the like is dissolved in water, and M(c〇i-yFey)〇3-6 composite oxide powder is stirred by stirring, ultrasonic dispersion or the like. Dispersed in the aforementioned solution and made into suspension 14 200846068 5

10 15

Further, after removing the moisture of the suspension solution and drying it, heat treatment is carried out at 7 Torr, and (4) a composite oxide (A) of M (C〇1 - yFey) 〇34 can be produced. ^ «The method of metal scales in heteroxia (10) is also not a special example. It can be made by the method of M(c, I). The same oxide of the same alloy holds the right metal with M (C°1_yFey). 〇3] The composite oxide (A) and the activated alumina carrying the noble metal are combined to form a catalyst for the invention of the invention, and the aforementioned mixture may be any of the wet type and the dry type. The right side may be any method such as a mortar mixing, a ball mill, a planetary ball mill, etc. The catalyst for exhaust gas purification of the present invention can be thinly applied to a ceramic or metal honeycomb to form a honeycomb catalyst for exhaust gas purification. In addition, the shouting hive that can be used in the present invention has no special relationship. For example, 2 = honeycomb, carbonized fossil honeycomb, etc., and the gold table which can be used in the present invention is also There is no particular limitation. For example, when the catalyst for exhaust gas purification of the present invention is thinly coated on the honeycomb, the first two 〇 and the Wei 7 knife are scattered with the catalyst and the bonding material. Wait for the slurry, and soak the honeycomb in -, and then 'n-binding agent can be solved, such as: nitrate, glue Oxidation, organic binder, etc., secondly, the remaining slurry on the surface of the honeycomb is removed by blowing or the like, and dried, then 5 〇〇 to 9 〇 (the temperature of rc is introduced into the atmosphere = several hours of treatment. The sputum can be applied to the mold of the material nest to be coated, so that the slurry is applied only to the inner wall of the honeycomb. 15 200846068

It is also possible to apply two types of exhaust gas purifying catalysts of the present invention having different A/B mass ratios to the gas inlet side and the outlet side of one honeycomb (Fig. 2(a), 2(b)), that is, In the second (a) and (b) drawings, the inlet side catalyst 6 is formed on the honeycomb substrate 8 (the content of the MCCotyFeyKV 5 composite oxide (A) carrying the noble metal is larger than that of the outlet side catalyst) and the outlet The side catalyst 7 (the amount of activated alumina (B) carrying the noble metal is more than that of the inlet side catalyst). In the catalyst of the present invention, as described above, since the HC which is partially oxidized by the M(c〇i_ yFey) 〇 3 - 5 composite oxide (A) carrying the noble metal can be utilized, the carrier can be used. The noble metal activated alumina (B) is effective for reducing NOx. Therefore, it is more desirable to increase the ratio of M(c〇i_ yFey)0" composite oxide (eight) on the inlet side of the noble metal compared to the outlet side. Therefore, the ratio of the A/B mass ratio R1 of the exhaust gas purifying catalyst on the inlet side to the a/b mass ratio R2 of the exhaust gas purifying catalyst on the outlet side is greater than Ri/R2 ratio! When it is 1 Torr or less, it is preferable to further improve the purification performance. If the ratio is below 丨, the purification performance cannot be further improved. On the other hand, even if it is larger than 1 〇〇, the active oxidation (B) of the noble metal held by the reduction of the effective X is reduced, so Further improve the purification performance. 20 The 2nd (4), 2_ is the thinner of the inlet side catalyst and the outlet side catalyst; the cloth range is not special, however, it is suitable for the honeycomb length 20~80%. The range is separately coated. In the production of the peak (4),) as thin as the coating: - A / B Berry than the different honeycomb honeycomb structure, but also any method of rape, for example, can be done by the following method _ separately modulate two kinds of liquids that have been dispersed with two kinds of exhaust gas catalysts with different mass ratios, and immerse the honeycombs into the U side from 16 200846068 to the desired side in thin coating on the inlet side. After the length, pull up and remove the excess slurry. After the coated honeycomb is dried or heat-treated, the second slurry is applied in the same manner from the opposite outlet side, and dried and heat-treated. In the honeycomb catalyst structure 5 in which the exhaust gas purifying catalyst of the present invention is applied thinly, as shown in the third (a), 3 (b), and 3 (c), the two kinds of A/B masses can be made. Inclining and reducing the coating amount separately from different catalysts, that is, the catalyst having the A/B mass ratio of R1 is inclined from the gas inlet side of the honeycomb toward the gas outlet side, reducing the coating amount, and the A/B mass ratio is The catalyst of the ruler 2 is inclined from the gas outlet side of the honeycomb toward the gas inlet side to reduce the amount of coating. Here, the ratio of R1/R2 is preferably greater than 1 and 10 is 100 or less. When the coating amount is inclined from the gas inlet side or the outlet side of the honeycomb as in the drawings 3(a), 3(b), and 3(c), it may be carried out by any method, for example, in the honeycomb After immersing the catalyst slurry in one of them, the remaining slurry is removed. However, at this time, the slurry having a high viscosity is used and the coating amount is inclined by the slow sag of the slurry, and the above treatment is carried out and 15 lines are dried. After the heat treatment, the other catalyst is similarly tilted in the opposite direction to the hive, and then dried and heat-treated to obtain the third (a), 3 (b), and 3 (c) images. The honeycomb catalyst structure coated with the exhaust gas purifying catalyst is as thin as shown. Further, as shown in Figs. 4(a) and 4(b), the MCCoi-yFey) 〇3 - ά composite oxide (8) 9 carrying the shell metal can be thinly coated on the honeycomb substrate 8 at the honeycomb. On the gas inlet side, the activated alumina (B) carrying the noble metal was thinly applied to the gas outlet side of the honeycomb to form a honeycomb structure for exhaust gas purification. The manufacturing method of the honeycomb catalyst structure is the same as the honeycomb catalyst structure of the second (a) and (b), and the fourth (a) and (b) are shown. 17 200846068 There is no particular limitation on the thin coating range of the mouth side catalyst (A) and the outlet side catalyst (B). However, it is preferable to carry out thin coating in the range of 30 to 70% of the honeycomb length. EXAMPLES Examples of the invention are described below, however, the invention is not limited to the examples of 5 and the like. (Example 1) IV^Coi-yFey). The 3-*? composite oxide is produced by the following method.

The raw materials of Sr and Ba are carbonates, the raw materials of Co and Fe are oxides, and the raw materials are weighed at a predetermined molar ratio and added with isopropyl alcohol (dispersion 10 medium) and pulverized by a ball mill. Wet mixing is carried out, and dreams are obtained to obtain a slurry. The solid component was separated from the slurry by a suction filter and dried at about 120 ° C for 1 hour. Secondly, the obtained dried solid was pulverized, and then baked at 950 ° C for 5 hours in an electric furnace by an electric furnace. A porous block-like calcined product was obtained. After the calcined product was pulverized, it was subjected to dry pulverization by an automatic mortar to prepare an MfOi-yFey) 〇3i composite oxide having the composition shown in Table 1. The pulverized oxide has an average particle diameter of h2//m and a specific surface area of 2.2 m 2 /g. Further, although the composition is used in the production amount, the chemically analyzed can be used to confirm the injected compound. The amount of metal elements in the composition is the same as that in the product. 2) Next, Pd and Zn are supported on the above-mentioned M(c〇i-yFey) 〇^d composite oxide, and the predetermined amount of nitrate of Pd and Rh is weighed and dissolved in In pure water, a 100 mL aqueous solution is prepared, and the aqueous solution and the oxide powder iOOg are placed in a rotary evaporator, and then red-transferred under normal temperature and reduced pressure, and the Φ riding defoaming treatment is performed, and at (4) atmospheric pressure. After heating 18 200846068 to about 60 thieves, decompress (4) water and dry. After cooling to normal temperature, the product was returned to the pressure and the paper was taken, and dried at the side t for 2 hours. Further, the obtained material f was subjected to mashing in the air for a minute and then pulverized. By the foregoing operation, it is possible to obtain the MCCOi-yFeJOH oxide (4) which is one or one of the precious metals which are supported by the catalyst of the present invention and which carries 0.6% by mass.

Next, Pd and Rh were supported on the active oxidation by the following method. Weighing the commercially available active oxidizing (4) Quantitative, dispersing it in a pure water towel to make a bulk dispersion of 100 mL, and, in this case, absorbing a mixture of pd, cadmium nitrate or Pd, Rh, which has been slightly dispersed, Further, an active oxidation precursor (8) of one or two kinds of noble metals carrying Pd or Rh in a carrying amount of 〇·6 parts by mass is obtained. The activated alumina used herein had an average particle diameter of 14 #m and a specific surface area of 90.6 m 2 /g. The specific surface area was measured by using 15 Belsorb manufactured by Bel Air Co., Ltd., and was determined by the BET method using nitrogen gas adsorption. Further, the particle size was measured by using a laser diffraction type particle size distribution manufactured by Shimadzu Corporation. The measuring device is used for measurement. Next, the noble metal oxide powder (A) and the noble metal-supporting activated alumina powder (B) are used to prepare a slurry, which is carried on a ceramic carrier 20 and a honeycomb metal carrier. Using the A/B mass ratio shown in Table 1, 19 parts by mass of a mixture of the noble metal oxide powder (A) and the noble metal-supporting r alumina powder (B) and 7 parts by mass of pure water were added while being disturbed. And 10 parts by mass of a commercially available methylcellulose solution (solid content: 2.5% by mass) as a binder, and an antifoaming agent was further added and 19 200846068 was sufficiently mixed to prepare a slurry.

The honeycomb body coated with the above-mentioned catalyst has a predetermined shape diameter of 25 cm, a 5 degree of 60 cm, and a cell hole size of a honeycomb cross section is a length imx horizontal length 20 200846068. A cylindrical type of 2 mm is not a honeycomb" The honeycomb is kept vertical, and the slurry having the excess amount of Lin is deposited on the upper end surface thereof, and is sucked from the lower end surface of the honeycomb to be applied to the inner wall of the honeycomb, and the remaining 16° is removed from the honeycomb. Wipe the attached i 5 liquid before drying, and continue to suck and blow the upper end surface of the honeycomb to dry. The honeycomb is reversed upside down, and the liquid coating and drying operation on the inner wall of the honeycomb is performed again, and then, in the atmosphere, (4). c heat treatment for a small hour, • #, the thin catalyst coated with the noble metal oxide powder (4) and the noble metal supported on the precious metal (g) (b) steel bee 10 nest catalyst structure Further, the total amount of metal fixed to the honeycomb is U to 1.6 g/L. The catalyst performance evaluation of the catalyst and the honeycomb catalyst structure uses the following method. First, an evaluation method for the exhaust gas purification property of the catalyst and the honeycomb catalyst structure will be described. • First, describe the evaluation method in the catalyst monomer (catalyst powder, catalyst particles). The evaluation apparatus used here is a flow-through type reaction apparatus comprising a stainless steel pipe, and the sample gas of the first table is introduced from the inlet side, and is distributed in the exhaust gas purification reaction unit to be discharged to the outlet side. Further, the sample gas is heated by the external 20 heater and sent to the exhaust gas purifying reaction portion, whereby the reaction portion can be heated and purified. The (inclusive) catalyst particles are placed in the column of the evaluation device, and the three conditions shown in Table 2 (rich-formal composition-poor) are periodically repeated while raising the temperature, and the NO decomposition is in a rich condition, CO and hydrocarbon. (hereinafter referred to as HC) analyzes the outflow side in the normal composition conditions (the catalyst portion is composed of 21 200846068) and obtains the rate of change of CO, HC, and NO concentrations, whereby the tearing of the body and the composition of the body are visible. =: After the change of the composition of the population gas, the inlet gas ^ ', , , and the time point of the text are determined, and then changed to other inlet gas, and the measurement is performed in the same manner. In the evaluation device of the present invention, the over-substitution π is repeated. The gas composition is measured just after the second, and is converted into other population gas composition readings.

The evaluation method of the catalytic performance of the honeycomb honeycomb structure. The environmental conditions of the formal composition conditions in Table 2 are taken from the material ~ Qing. c After maintaining the honeycomb 10 catalyst structure for 1 hour, it was once cooled to near normal temperature, and then placed in the shell, and the rate of change of each concentration of (3), HC, and NO was investigated by the same procedures and conditions as described above. (purification characteristics), and the space velocity is set to 50,000 hr_1. Table 3 shows the evaluation results of the aforementioned catalyst properties. Compared with the comparative example No. 1 - 33 to 1 - 36 which uses the contact medium (A) or the catalyst (B) alone, the embodiment version is used! ～1-32 can improve the purification performance, and although the oxygen absorbing material is not contained in the present invention, the purification performance is high even in this state. Table 2 Conditions for the sample gas composition before purification (vol%) n2 C02 C3H6 CO h2 〇2 NO Rich 82.925 13.8 0.040 2.04 0.68 0.49 0.025 Regular composition 84,985 13.8 0*040 0.49 0.17 0.49 0.025 Poor 83.975 13.8 0.040 0.49 0.17 1.50 0.025 22 20 200846068

Table 3 No. Total amount of precious metals fixed to the honeycomb (g/L) Purification characteristics of the catalyst; Catalyst performance of the 300° 〇 honeycomb catalyst structure (300° 〇 CO CO NO NO HC HC NO 1 — 1 1.1 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Example 1-4 ◎ ◎ ◎ ◎ ◎ ◎ Example 1-5 1.1 ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Example 1-10 1.1 ◎ ◎ ◎ ◎ ◎ Example 1-11 1.1 ◎ ◎ ◎ ◎ ◎ ◎ Example 1-12 1.1 ◎ ◎ ◎ ◎ ◎ ◎ Example 1-13 1.1 〇〇〇〇〇〇Implementation Example 1 - 14 1.1 〇〇〇〇〇〇 Example 1-15 1.1 〇〇〇〇〇〇 Example 1-16 1.1 〇〇〇〇〇〇 Example 1-17 1.1 ◎ ◎ ◎ ◎ ◎ ◎ Example 1 -18 1.1 ◎ ◎ ◎ ◎ ◎ ◎ Example 1-19 1.6 ◎ ◎ ◎ 〇 ◎ ◎ Real Example 1-20 1.6 ◎ ◎ ◎ 〇 ◎ ◎ Example 1-21 1.6 ◎ ◎ ◎ 〇 ◎ ◎ Example 1-22 1.6 ◎ ◎ ◎ 〇 ◎ ◎ Example 1-23 1.6 ◎ ◎ 〇 ◎ ◎ 〇 Example 1-24 1.6 ◎ ◎ 〇 ◎ ◎ 〇 Example 1-25 1.1 〇〇〇〇〇〇 Example 1-26 1.1 〇〇〇〇〇〇 Example 1-27 1.1 ◎ ◎ 〇 ◎ ◎ 〇 Example 1- 28 1.1 ◎ ◎ 〇 ◎ ◎ 〇 Example 1-29 1.1 ◎ ◎ 〇 ◎ ◎ 〇 Example 1-30 1.1 ◎ ◎ 〇 ◎ ◎ 〇 Example 1-31 1.1 〇〇〇〇〇〇 Example 1 — 32 1.1 〇〇〇〇〇〇Example 1-33 L1 〇〇X 〇〇X Comparative Example 1-34 1.1 Δ Δ 〇Δ Δ 〇 Comparative Example 1-35 1.1 Δ Δ X Δ △ X Comparative Example 1 - 36 1.1 Δ Δ Δ Δ Δ Δ Comparative Example * Purification rate: ◎: 90 to 100%, 〇: 70 to 90%, Δ · · 50 to 70%, X: 0 to 50% 23 200846068 (Example 2) by way of example In the same manner, the SrCoO" composite oxide produced by the same method as in Example 1 was carried in an amount of 〇·6 parts by mass. Pd, and modulate the carrier P(^SrC〇〇"composite oxide (4), the other side of the five sides, and the implementation of the life (1) in the same amount of support 〇 5 mass parts of the active oxidation in the name of Rh, and modulation Hold the active oxidation of Rh (8). As shown in Table 4, the ratio of (Α) and (B) is adjusted to modulate the catalyst, and the catalyst thus prepared is divided into gas inlets as shown in Figs. 2(a) and 2(b). The side and the outlet side were thinly applied to the ceramic honeycomb and the stainless steel honeycomb by the same method as in Example 1 to form a honeycomb catalyst structure. Further, the slurry concentration is set to 2 times, and as shown in the figures 3(a), 3(b), and 3(c), first, the catalyst (A) is thinly coated and the gas inlet side is increased during the drying process. In addition, the catalyst (B) was thinly coated, and the gas outlet side was similarly thickened to prepare a honeycomb catalyst structure in which the coating amount was inclined. The evaluation method of the catalytic performance of the honeycomb catalyst structure was the same as that of Example 1, and Table 5 shows the evaluation results.

Table 4

No. Gas inlet side gas outlet side A/B mass ratio (R1) Relative to honeycomb length gas seat length (%) A/B mass ratio (R2) Relative to honeycomb length coating length R1/R2 2-1 5 50 0.5 50 10 2 — 2 1 , 50 0.2 50 5 2-3 10 10 0.1 90 100 2-4 1 80 0.1 20 10 2—5 1 80 0.1 20 10 2-6 1 90 0.5 10 2 2-7 ϊ 1 50 1 50 1 2-8 0.5 50 1 50 0.5 2— 9 2 Coating 1 from the gas inlet roll slanting reduction 1 Coating from the gas outlet side inclination reduction 2 24 200846068 Table 5

No. Total amount of precious metal fixed to the honeycomb (g/L) Catalyst performance of the honeycomb catalyst structure (300°〇CO HC NO 2—1 1.1 ◎ ◎ ◎ 2-2 li ◎ ◎ ◎ 2-3 1.1 ◎ ◎ ◎ 2 — 4 1.1 ◎ ◎ ◎ 2-5 1.1 ◎ ◎ ◎ 2-6 1.1 ◎ ◎ ◎ 2-7 1.1 ◎ ◎ 〇 2-8 1.1 〇〇〇 2-9 1.1 ◎ ◎ ◎ * Purification rate ·· ◎ : 90 to 100%, 〇: 70 to 90%, △ · _ 50 to 70%, X: 0 to 50% 5 As shown in Table 5, the catalyst for purification of the present invention is thinly coated and the coating amount is tilted. The media structures (Νο·2 - 1 to 2 - 9) all showed good catalyst properties. (Example 3) # As shown in Table 6, by the same method as in Example 1, the carrying amount was 0.6 10 The Μγοι -. yFey) 03-5 composite oxide prepared by the same method as in Example 1 carries Pd, Rh, and is prepared to carry a noble metal.

On the other hand, in the same manner as in Example 1, 0.5% by mass of the supported alumina was used to carry Pd and Rh in the activated alumina, and the noble metal-supporting activated alumina (B) was prepared. The catalysts 15 prepared as described above are divided into a gas inlet side and an outlet side as shown in the fourth (a) and fourth (b), and are thinly coated on the ceramic honeycomb and the stainless steel honeycomb by the same method as in the first embodiment. Make a honeycomb catalyst structure. Evaluation of Catalyst Performance of Honeycomb Catalyst Structure 25 200846068 The legal system is the same as that of Example 1, and Table 7 shows the evaluation results. Table 6

No. Oxide powder carrying precious metal (A) Composition of noble metal M(C〇i-yFey) carrying activated magnesium powder (B) carrying noble metal 3 - <5 composite oxidation [Mo Erbi ) Supporting precious metals Ba Sr Co Fe 3-1 0 1 1 0 Pd Rh 3-2 〇1 0 1 Pd Rh 3-3 0 1 1 0 Pd, Rh P d, Rh 3-4 0 1 0 1 Pd, Rh Pd, Rh 3-5 0.5 0.5 0.8 0.2 Pd Rh 3-6 0.5 0.5 0.2 0.8 Pd Rh Table 7

No. Coating length of noble metal oxide powder (A) relative to honeycomb length (%) Active alumina powder carrying precious metal (B) Coating length relative to honeycomb length (%) Total amount of precious metal fixed to honeycomb (g/L) Honeycomb angle 〗 〖Competing properties of η i media structure (300°〇CO HC NO 3-1 50 50 1.1 ◎ ◎ ◎ 3 — 2 50 50 1.1 ◎ ◎ ◎ 3 — 3 50 50 1.6 ◎ ◎ 〇3-4 50 50 1.6 ◎ ◎ 〇3 1 5 60 40 1·1 〇〇〇3-6 60 40 1.1 〇〇〇

* Purification rate: ◎: 90 to 100%, 〇: 70 to 90%, Δ: 50 to 70%, 5 x: 0 to 50% As shown in Table 7, the purification catalyst of the present invention is divided into gas inlet side The honeycomb catalyst structures (No. 3 - 1 to 3 - 6) which are thinly coated with the gas outlet side all exhibit good catalytic properties. 10 INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is possible to reduce the amount of metal used in the use of Pt 26 200846068 and to form a ternary catalyst which does not contain a high-priced rare earth element, and can be greatly reduced. The cost of the exhaust gas purifying converter, in addition, the holding of the V^Coi-yFeJO3·^ system carrying the Pt-free shell metal is responsible for the oxidation of CO and the partial oxidation of HC, and the active oxidation of the noble metal containing no Pt Aluminum promotes the reduction and purification of NOx from the partially oxidized HC of the industry 5, and since the above two kinds of catalysts can be added to the exhaust gas purification, even if it is not used? By reducing the amount of precious metal used, high catalyst performance can also be achieved. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the catalyst 10 for exhaust gas purification of the present invention applied to a honeycomb substrate and a schematic view for explaining an exhaust gas purifying reaction. Fig. 2(a) is a schematic perspective view showing the honeycomb structure for exhaust gas purification in which the exhaust gas purifying catalyst of the present invention having a different mass ratio of Α/Β is applied to the gas inlet side and the outlet side of one honeycomb. . Fig. 2(b) is a schematic view showing the honeycomb structure for exhaust gas purification in which the two types of gas purification catalysts of the present invention having different mass ratios of ruthenium and osmium are applied to the gas inlet side and the outlet side of one honeycomb. Partial cross-section of the interior of the hive. Fig. 3(a) is a schematic perspective view showing a honeycomb structure for exhaust gas purification in which the amount of coating of the exhaust gas for purifying the present invention is different, and the coating amount is inclined. 20th (b) is a schematic partial cross section of the honeycomb structure of the honeycomb structure for exhaust gas purification in which the exhaust gas purifying catalyst of the present invention is coated with two types of enthalpy/Β mass ratios, and the coating amount is inclined. Figure. Fig. 3(c) is a view showing another example of thin coating of the exhaust gas purifying catalyst of the present invention having two different a/b mass ratios and tilting the coating amount 27 200846068 Partial cross-section of the interior of the hive. Figure 4(a) shows that the MfOi-yFey)03-d composite oxide (A) carrying the noble metal of the present invention is thinly coated on the gas inlet side of the honeycomb, and the activated alumina carrying the noble metal (B) A schematic perspective view of a honeycomb structure for exhaust gas purification which is thinly applied to the gas outlet of the honeycomb *5 side. • Figure 4(b) shows the thin coating of the MCCoi-yFey)03i composite oxide (A) containing the precious metal of the present invention on the gas inlet side of the honeycomb, and the activated alumina (B) carrying the noble metal. A partial cross-sectional view of the interior of the honeycomb that is thinly applied to the honeycomb structure for exhaust gas purification on the gas outlet side of the honeycomb. 10 [Description of main components] U...Precious metal 5,8...Hive base 2,9...M(C〇i-yFey)〇3 - 5 Composite 6...Inlet side catalyst oxide 7.. .Export side catalyst 4,10...activated alumina 28

Claims (1)

200846068 X. Patent application scope: L A catalyst for exhaust gas purification, comprising: one or two kinds of oxides containing noble metals of Pd or Rh _〇〇1~/00〇3-, (here, ^^ is a combination of element 5 selected from 83 or 81' and y is 〇~1, δ is determined to satisfy the value of charge neutrality condition) (Α); and a noble metal carrying Pd or Rh One or two of the active oxidations (B). 2. The catalyst for exhaust gas purification according to the first aspect of the invention, wherein the noble metal supported on the oxide (A) is Pd, and the noble metal supported on the active aluminum oxide (B) is Rh. 3. The catalyst for exhaust gas purification according to claim 1 or 2, wherein the noble metal oxide M (Co _ yFey) 〇 3 - δ (A) and activated alumina (Β) are carried. The mass ratio of Α/Β is 0.1 to 1〇. 15 4. The catalyst for exhaust gas purification according to item 1 of the patent application, wherein the above-mentioned ^^ value is 0 · 2^ 1 〇 5 · a honeycomb catalytic structure for exhaust gas purification, which will apply for a patent garden The catalyst for exhaust gas purification according to any one of items 1 to 4 is thinly coated on a ceramic or metal honeycomb. 20 6. The honeycomb catalyst structure for exhaust gas purification according to item 5 of the patent application, wherein the honeycomb/gas mass ratio R1 of the exhaust gas purification catalyst of the honeycomb on the gas inlet side and the gas purification side of the gas outlet side The ratio of the α/β mass ratio of the catalyst to the R2 system R1/R2 is more than 1 and is 1 Å or less. 7. The honeycomb catalyst structure for exhaust gas purification according to item 5 of the patent application, 29 200846068 wherein the coating amount of the exhaust gas purifying catalyst having the A/B mass ratio of R1 is from the gas inlet side of the honeycomb The coating amount of the exhaust gas purifying catalyst that is inclined toward the gas outlet side and the A/B mass ratio is R2 is inclined from the gas outlet side of the honeycomb to the gas inlet side, and is reduced by 5, and The ratio of R1/R2 is greater than 1 and is less than 1 。. *8· A honeycomb catalyst structure for exhaust gas purification, which is one or two kinds of oxides M (Co yFeJCV) carrying a noble metal of Pd or Rh, (in φ, M is substantially selected from Ba) Or a combination of elements of Sr, and y is 〇 卜 卜 卜 系 系 系 系 系 卜 卜 ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( ( One or two kinds of noble metal oxides (B) are thinly coated on the gas outlet side of the honeycomb. 9·The honeycomb catalyst structure for exhaust gas purification according to item 8 of the patent scope, wherein the carrier The noble metal of the oxide (A) is Pd, and the noble metal supported on the activated alumina (B) of the first 15 is Rh. • 1〇·The honeycomb catalyst structure for exhaust gas purification according to claim 8 Miscellaneous, wherein the aforementioned y value is 0.2 to 1. 30